Conventionally, inspecting and managing air pressure of tires mounted on vehicles has been desirable from the perspectives of enhancing tire durability, wear resistance, fuel economy, riding comfort, and driving performance. Therefore, various systems for monitoring air pressure of tires have been proposed. Generally, in such a system, an obtaining device that obtains information about air pressure of tires mounted on a vehicle and transmits that information is provided in the tire cavity regions of each wheel, and a monitoring unit monitors the air pressure of the tires obtained by the obtaining device that obtains the air pressure information of the tires (see, for example, Japanese Unexamined Patent Application Publication No. 2008-1222).
The obtaining device described in Japanese Unexamined Patent Application Publication No. 2008-1222 has a tire pressure monitoring system (TPMS) valve that measures and transmits the air pressure in the tire cavity region, and an L-shaped air valve that penetrates the rim, and the TPMS valve and the L-shaped air valve are configured to allow connection therebetween. Ventilation is produced between the tire cavity region and the atmosphere outside of the tire due to air passages provided in both valves being connected when both valves are connected.
Puncture repair liquid to be injected inside the tire cavity region interposed between the tire and the rim is often used when a puncture occurs in a tire. Since the puncture repair liquid is in a liquid form, the puncture repair liquid adheres to the inner surface of the tire that faces the tire cavity region and may even adhere to the obtaining device provided in the tire cavity region when the puncture repair liquid is injected into the tire cavity region. In some cases, the puncture repair liquid solidifies and covers an opening provided in the obtaining device for sensing the air pressure, thus becoming a problem that adversely affects the measurement of the air pressure.
To resolve this problem, a tube may be inserted into the tire cavity region from the tire valve so that the puncture repair liquid inside the tire cavity region can be exhausted through the tube.
However, since the obtaining device in Japanese Unexamined Patent Application Publication No. 2008-1222 has an L-shaped air valve, it is difficult to insert the tube into the tire cavity region through the air valve. As a result, there is a concern that the puncture repair material may not be recovered.
Furthermore, since the obtaining device in Japanese Unexamined Patent Application Publication No. 2008-1222 is provided with a sensor unit for detecting the air pressure in the tire cavity region exposed in the vicinity of an opening part of an air passage formed on the surface of the TPMS valve facing the tire cavity region, there is a concern that the puncture repair liquid may adhere to the sensor unit when the puncture repair liquid is injected into the tire cavity region.